Wedge anchor for concrete

ABSTRACT

An expansion wedge anchor for insertion in a hole delimited by a wall comprises an expander member and an expansion member, the expander member being provided at a leading end of the expander member, the expander member comprising a flaring end, the expansion member being expandable at a trailing end thereof and being adapted to engage the wall of the hole when the expander member is positioned in the hole, wherein upon longitudinal withdrawal of the expander member from the hole, the expander member displaces longitudinally relative to the expansion member with the flaring end thereof gradually causing the trailing end of the expansion member to expand, whereby a trailing edge of the expansion member engages the wall of the hole. The trailing end is adapted, when expanded by the flaring member, to extend at an angle with respect to a longitudinal axis of said expander member. In the method of setting the expansion wedge anchor in the hole, the following steps are found: (a) providing an expander member and an expansion member; and (b) displacing the expander member such as to cause a trailing end of the expander member to engage the wall of the hole.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application is a Continuation of U.S. patent application Ser. No.11/011,755 filed on Dec. 14, 2004 (now U.S. Pat. No. 7,587,873 issued onSep. 15, 2009), which is a Continuation of U.S. patent application Ser.No. 09/857,403 filed on Jun. 1, 2001 (now U.S. Pat. No. 6,829,871 issuedon Dec. 14, 2004), which is a National Entry Application of PCTApplication No. PCT/CA99/01129 filed on Dec. 1, 1999, which claimspriority on U.S. Provisional Application No. 60/110,530 filed on Dec. 1,1998. All documents above are herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to fasteners and, more particularly, toexpandable fasteners for mounting to concrete structures, and the like.

2. Description of the Prior Art

Expandable anchors of many different types are already known. Moreparticularly, expandable anchors have been developed for insertion intoa hole formed in a support structure such that a cylindrical expansionsleeve of the anchor may be selectively expanded into frictional contactwith the inside peripheral surface of the hole such that the anchorbecomes frictionally anchored in the support structure. Typically, theexpandable anchor includes an elongated expander member having athreaded first end and a flared second end opposite the first end with acylindrical surface extending between the first and second ends aroundwhich there is provided the aforementioned expansion sleeve. Thethreaded first end is like a headless screw and extends outwardly of thesupport structure once the expandable anchor is positioned in the holethereof. A nut threaded on the visible part of the threaded first endmay be used as an actuating mechanism with an object to be secured tothe support structure being typically located between the nut and thesupport structure as the threaded first end of the expandable anchorextends through this object. By rotating the nut, it engages the outersurface of the object and thus bears upon it such as to pull theexpander member in an outward direction. As the expansion sleeve isalready sufficiently frictionally engaged with the inside surface of thehole, when the expandable anchor is pulled by the rotation of the nut,the expansion sleeve stays substantially stationary in the hole andthus, as the expander member is pulled out of the hole, the flaredsecond end of the expander member causes the cylindrical expansionsleeve to expand radially outwardly thereby increasing a frictionbetween the expansion sleeve and the hole and thus further securing theexpandable anchor therein.

Since the expansion sleeve must already be frictionally engaged with thehole before the expandable anchor is pulled, the outside diameter of theexpansion sleeve must be similar to, even slightly greater than, theinside diameter of the hole in order to ensure an initial frictionalcontact therebetween which will then allow the expansion sleeve toremain still in the hole while the expander member is pulled outwardlythereof and thus allow the expansion sleeve to be expanded by the flaredend of the expander member. This diameter of the expander member, atrest, results in that the expandable anchor when initially inserted inthe hole must be inconveniently driven with significant force therein asthe expansion sleeve is already frictionally engaged with the insidewall of the hole. The flared end then acts as a wedge to expand theexpansion sleeve into greater frictional contact with the inside of thehole.

For instance, U.S. Pat. No. 2,647,431 issued on Aug. 4, 1953 to Lewisdiscloses an expansion bolt comprising a hollow shell having a leadingend adapted to be expanded by a wedge into frictional contact with theperipheral wall of a hole. Resilient spurs, in some cases as part of aseparate bail, are provided at opposite trailing ends of the shell, i.e.the end which is nearest to the opening of the hole, in order to engagethe wall of the hole and prevent initial rotation of the shell relativeto the hole until the shell frictionally engages the wall.

U.S. Pat. No. 3,250,170 issued on May 10, 1966 to Siegel, U.S. Pat. No.3,620,120 issued on Nov. 16, 1971 to Warner, U.S. Pat. No. 4,337,012issued on Jun. 29, 1982 to Sohnius, U.S. Pat. No. 4,403,894 issued onSep. 13, 1983 to Clark, U.S. Pat. No. 5,028,188 issued to Jul. 2, 1991to Prince and U.S. Pat. No. 5,344,257 issued on Sep. 6, 1994 to Wrightet al. all disclose to expand a shell in a direction normal to a holeaxis such that the periphery of the shell frictionally engages a wall ofthe hole. Notably, U.S. Pat. Nos. 3,620,120, 5,028,188 and 5,344,257each describes having a resilient shell for facilitating theintroduction of the expandable anchor within a hole while providingsufficient holding pressure to prevent the shell and associated wedgemember from spinning in the hole as a torque is applied to a bolt foraxially displacing the wedge member such as to radially expand theshell.

U.S. Pat. No. 2,783,673 issued on Mar. 5, 1957 to Lewis et al. and U.S.Pat. No. 5,352,066 issued on Oct. 4, 1994 to Schaeffer et al. also bothdisclose an expandable shell for facilitating the installation thereofwithin a hole. The leading end of the shell may be expanded at an anglewith respect to the central axis of the hole.

Also known are undercut wedge anchors, wherein the hole formed in thesupport structure is enlarged with a tool at a distance from the visibleopening of the hole such that the expandable undercut wedge anchor maythereafter be inserted in the hole until its expansion sleeve becomeslocated behind a shoulder defined at the junction of the enlarged areaand the remainder of the hole. Once expanded, the expansion sleeve mayabut this shoulder and thus retain the anchor in position in the supportstructure.

SUMMARY OF THE INVENTION

It is therefore an aim of the present invention to provide an improvedexpandable wedge anchor for use in holes in various materials, e.g.concrete.

It is also an aim of the present invention to provide an expandablewedge anchor having an expander member and an expansion member capableof spring-like deformation.

It is a further aim of the present invention to provide an expandablewedge anchor wherein the expansion member is capable of being expandedat a trailing end thereof.

It is a still further aim of the present invention to provide anexpandable wedge anchor wherein the expansion member may be rotated inthe hole such that its trailing end produces an undercut in the holeinto which the expanded trailing end nests.

It is a still further aim of the present invention to provide a spiralwedge anchor also in accordance with the present invention.

Therefore, in accordance with the present invention, there is providedan expansion wedge anchor for insertion in a hole delimited by a wall,comprising an expander means and an expansion means, said expansionmeans being provided at a leading end of said expander means, saidexpander means comprising flaring means, said expansion means beingexpandable at a trailing end thereof and being adapted to engage thewall of the hole when said expander means is positioned in the hole,wherein upon longitudinal withdrawal of said expander means from thehole, said expander means displaces longitudinally relative to saidexpansion means with said flaring means thereof gradually causing saidtrailing end of said expansion means to expand, whereby a trailing edgeof said expansion means engages the wall of the hole.

More particularly, said trailing end is adapted, when expanded by saidflaring means, to extend at an angle with respect to a longitudinal axisof said expander means.

Also in accordance with the present invention, there is provided amethod of setting an expansion wedge anchor in a hole delimited by awall, comprising the steps of: (a) providing an expander member and anexpansion member; and (b) displacing said expander member such as tocause a trailing end of said expansion member to engage the wall of thehole.

More particularly, in step (b), said trailing end is expanded such as toextend at an angle with respect to a longitudinal axis of said expandermember.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus generally described the nature of the invention, referencewill now be made to the accompanying drawings, showing by way ofillustration a preferred embodiment thereof, and in which:

FIGS. 1A and 1B are longitudinal cross-sectional views of a firstvariant of a non-slip wedge anchor in accordance with the presentinvention shown respectively in at rest and installed positions thereof;

FIG. 1C is a bottom plan view of the anchor of FIG. 1A;

FIGS. 2A and 2B are longitudinal cross-sectional views of a secondvariant of a non-slip wedge anchor in accordance with the presentinvention shown respectively in at rest and assembled positions thereof;

FIGS. 3A and 3B are respectively elevational and bottom plan views of anexpander member of the anchor of FIGS. 2A and 2B;

FIGS. 3C, 3D and 3E are respectively front elevational, side elevationaland bottom plan views of an expansion member of the anchor of FIGS. 2Aand 2B;

FIGS. 4A and 4B are longitudinal cross-sectional views of a thirdvariant of a non-slip wedge anchor in accordance with the presentinvention shown respectively in at rest and assembled positions thereof;

FIGS. 5A and 5B are respectively elevational and bottom plan views of anexpander member of the anchor of FIGS. 4A and 4B;

FIGS. 5C, 5D and 5E are respectively front elevational, side elevationaland bottom plan views of an expansion member of the anchor of FIGS. 4Aand 4B;

FIGS. 6A and 6B are longitudinal cross-sectional views of a fourthvariant of a non-slip wedge anchor in accordance with the presentinvention shown respectively in at rest and assembled positions thereof;

FIGS. 7A and 7B are respectively elevational and bottom plan views of anexpander member of the anchor of FIGS. 6A and 6B;

FIGS. 7C, 7D and 7E are respectively front elevational, side elevationaland bottom plan views of an expansion member of the anchor of FIGS. 6Aand 6B;

FIGS. 8A and 8B are longitudinal cross-sectional views of a firstvariant of an undercut wedge anchor in accordance with the presentinvention shown respectively in first and second positions thereof in asupport structure;

FIGS. 9A to 9D are respectively front elevational, side elevational,bottom plan and top plan views of an expander member of the undercutwedge anchor of FIGS. 8A and 8B;

FIGS. 9E to 9G are respectively front elevational, side elevational andbottom plan views of an expansion member of the undercut wedge anchorFIGS. 8A and 8B;

FIGS. 10A to 10D are respectively front elevational, side elevational,bottom plan and top plan views of a second variant of an undercut wedgeanchor in accordance with the present invention;

FIGS. 11A to 11C are respectively front elevational, side elevationaland top plan views of a third variant of an undercut wedge anchor inaccordance with the present invention;

FIGS. 12A to 12C are respectively front elevational, side elevationaland bottom plan views of a fourth variant of an undercut wedge anchor inaccordance with present invention;

FIGS. 13A to 13C are respectively front elevational, side elevationaland bottom plan views of a fifth variant of an undercut wedge anchor inaccordance with present invention;

FIG. 14A is a front elevational view of a spiral wedge anchor also inaccordance with the present invention;

FIG. 14B is a variant of the spiral wedge anchor of FIG. 14A;

FIG. 14C is a top plan view of either anchor of FIGS. 14A and 14B; and

FIG. 15 is a vertical cross sectional view showing the spiral anchorwedge of FIG. 14A in an expanded position within a hole defined in asupport structure such that the anchor retains an object to this supportstructure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A) Non-Slip Wedge Anchors(FIGS. 1 to 7)

The purpose of this new non-slip expansion anchor concept is to providean improved anchor design capable of achieving superior performance overconvention al type expansion anchors presently offered. Another area tobe considered is that of the effect of vibratory loading on the anchorperformance. This is relevant considering the anchor is designed toprovide minimal relaxation of the anchor assembly after installation. Inconventional expansion anchors the bolt tends to loosen after theinitial setting torque has been applied and as a result it must bere-tightened to establish the proper clamping load. The positive setbetween the anchor bolt and clip segments will provide minimal slip orcreep once the anchor is set and the load is applied to the anchor.

FIGS. 1A and 1B illustrate a non-slip wedge anchor 10 in accordance withthe present invention which is shown respectively in at rest andinstalled positions thereof. In FIG. 1C, the anchor 10 is seen from itsunderside. The anchor 10 includes an expander member 12 and an expansionmember 14. The expander member 12 is designed to be inserted in a hole Hdefined in a support structure S, such as a concrete element, andcomprises a treaded section 16 adapted to extend in the hole H whilehaving a proximal end 18 which extends outside of the hole H such as tobe engaged by a threaded female member, such as a nut N, with a washer Wbeing herein shown between the nut N and the support structure S.Typically, an object, although not herein shown, is held by the anchor10 to the support structure S; it is noted that, in the presentembodiment, as well as in the other embodiments of the various anchorsherein shown and described, such an object has not been illustrated.

The expander member 12 also includes a flared distal end 20 around whichis provided the expansion member 14 which is dimensioned to frictionallyengage the walls of the hole. Once the anchor 10 has been introduced inthe hole H, the nut N is rotated to displace the expander member 12translationally outwardly of the hole H, As the friction forces betweenthe expansion member 14 and the hole H are sufficient for it to remainstationary therein during the displacement of the expander member 12,the flared end 20 of the expander member 12 causes the expansion memberto expand, as seen in FIG. 1B, thereby anchoring the anchor 10 in thehole H. The expansion member includes a double-layered, folded over,proximal or trailing end 22 which defines an internal abutment shoulder24 which can be engaged by an enlarged annular flange 26 provideddistally of the flared end 20 of the expander member 12.

In FIGS. 2A and 2B, a second wedge anchor 30 in accordance with presentinvention is illustrated and which comprises an expander member 32(shown in detail in FIGS. 3A and 3B) and an expansion member 34 (shownin detail in FIGS. 3C to 3E), or expandable clip. The expander member 32is similar to the expander member of FIG. 1A in that it includes atreaded section 36, having a proximal end 38, a leading flared end 40and a reduced diameter intermediate cylindrical section 42 therebetween.A shoulder 44 is defined at a junction of the intermediate and threadedsections 42 and 36.

The expansion member 34 comprises a leading support 46, an expandablecollar 48 and a leg 50 connecting the support 46 and collar 48 together.The collar 48 is split at 52 to allow it to expand, as seen in FIG. 2B,and defines thereat mating tongue and groove elements 54 and 56,respectively. As seen in FIGS. 2A and 2B, the leg 50 of the expansionmember 34 is held captive in a groove 58 defined longitudinally in theflared end 40 (see FIGS. 3A and 3B) thereby preventing the expansionmember 34 from rotating with respect to the expander member 32 andforcing it to work vertically without twisting.

In operation, the rotation of the nut N causes the expander member 32 todisplace longitudinally and outwardly along the hole H. As the collar 48of the expansion member 34 frictionally engages the walls of the hole H,it remains stationary therein while the groove 58 slides along the leg50. It is noted that the leg 50 is biased outwardly, i.e. to an open ordeployed position, to ensure the initial frictional engagement of thecollar 48 with the walls of the hole H. It is also noted that theoutside surface of the collar 48 is knurled for additional friction.

The partial withdrawal of the expander member 32 from the hole H causesthe flared end 40 to expand outwardly the collar 48 with a trailing edge60 of the collar 48 engaging the walls of the hole H at an angle withrespect to a longitudinal axis of the hole H (see FIG. 2B). Such anengagement with the hole H at a trailing end of the expandable member34, and with an angle opposed to that of the flared end 40, is verysecure and increases the force required to pull out the expanded anchor30 from the support structure S.

It is noted that the cylindrical intermediate section 42 allows thecollar 48 to be received in a collapsed position (see FIG. 2A) when theanchor 30 is initially driven in the hole H. Also, the shoulder 44prevents the expandable member 34 from moving up on the threaded section36 of the expander member 32. The tongue and groove elements 54 and 56align the collar 48 at its split 52 to provide a peripheral, 360°-like,gripping of the expandable member 34 into the walls of the hole H.

The expandable member 34 is also provided on its leg 50 with areinforcement rib 62 to provide more rigidity to the leg 50. The leadingsupport 46 of the expandable member 34 comprises a concave bottom 64 tostill give more rigidity to the leg 50. At the very end of the flaredsection 40 of the expander member 32 is a radial flat section land 66 toallow for maximum interference between the hole H, the expander member32 and the expansion member 34.

In the following descriptions which pertain to variants of the anchor 30of FIGS. 2A and 2B, components which are identical in function and instructure to corresponding components of the anchor 30 bear the samereferences as in FIGS. 2A to 3E, whereas similar parts have beenattributed suffixes to their reference numerals with respect to thenumerals used in FIGS. 2A to 3E. Any components which are new to theanchors of the following variants are identified by new referencenumerals.

In FIGS. 4A to 5E and 6A to 7E, third and fourth wedge anchors 70 and80, respectively, also in accordance with present invention areillustrated. These anchors 70 and 80 are very similar to the anchor 30,except that their respective expansion members 34 a and 34 b haverespectively 2 and 3 legs 50 a and 50 b, respectively, as opposed to thesingle leg 50 embodied in the expansion member 34 of anchor 30. Themultiple splits 52 b result in that the collar 48 b includes three clipsegments.

The expansion member 34 b of anchor 80 defines a pair of rounded radii82 and 84 to increase the rigidity of the legs 50 b.

Therefore, with respect to the anchor of FIGS. 6A to 7E′, the new wedgeconcept is made up of two components. One is a specially formed stud orexpander member which is partially threaded at one end. Assembled to thebottom end is a multi segment expansion clip or expansion member whichis assembled to the flared end of the stud opposite the threaded end.

The stud (FIGS. 7A and 7B) is made of high strength steel which can beheat treated for heavy duty applications. The stud is unique in that itcontains a number of features unlike conventional wedge type anchors.The stud is comprised of an external thread at one end which has areduced diameter at the bottom end of the thread which engages the multisegmented clip. The difference in diameter prevents the clip fromtravelling upward onto the threads of the bolt. The end of the boltopposite to the thread end has a flared section extending outward. Theend of the flare incorporates several guide segments used to maintainthe position of the expansion member as it expands during installationand is also used to prevent rotation of the total clip itself. At thevery end of the flared section of the bolt is a radial flat section landto allow for maximum interference between the hole, stud and expansionclip.

The expansion clip (FIGS. 7C to 7E) is made of high strength steel andis comprised of three formed segments which are pre-expanded prior toassembly. Each of the segments compresses against the hole in theconcrete when driven into the hole providing frictional resistance toaxial pullout during installation and after the load is applied.

Each segment is connected to a formed concave shaped section via aformed leg section. Each leg connecting a segment has a strengtheningrib and internal radii to add rigidity to the clip assembly. Anotherfeature located on each segment is a locking tab which helps controlexpansion and keep the clip segments in line. This provides for a full360 degree expansion. A portion of each is knurled to provide additionalfriction and holding power.

Anchor Installation/Function

A nut/washer is assembled to the threaded end of the stud assembly. Theembedment is determined and measured from directly under the washer tothe bottom end of the bolt. The anchor is driven into a pre-drilled holein the concrete. As the anchor is driven into the hole using a hammer,the pre-expanded segments of the clip assembly provide the frictionalresistance to resist the axial pullout resulting during the initialsetting of the anchor.

As the installation torque is increased, the nut is tightened flushagainst the flat washer and the concrete. As a result the taperedportion at the bottom of the stud is pulled upward into the clipsegments causing expansion of the lower clip segments located toward thebottom portion of the bolt (see FIG. 6B). The constant outward forceprovided by the upper section of the segments cause the clip segments todig into or interfere with the concrete thus preventing the clipassembly from sliding or creeping upward which causes the bolt to loosenin the hole of the concrete. Once the installation torque is reached,the load can be applied to the bolt.

B) Undercut Wedge Anchor (FIGS. 8 to 13)

The purpose of this undercut type anchor concept is to provide a highstrength instant holding mechanical type anchor designed to achievesuperior pullout performance in concrete while provided a positive lockinto the concrete to prevent anchor slip or creep.

The feature of being instant holding makes it suitable for applicationsneeding to apply the load immediately which is not the case withchemical type anchors. This anchor must be capable of withstanding bothvibratory and shock type loads without failure. Failure would bedetermined by the improved load versus displacement relationship.

FIGS. 8A and 8B illustrate an undercut wedge anchor 100 in accordancewith the present invention which is shown respectively in first andsecond positions thereof in a support.

The undercut anchor 100 consists of two specially formed components,namely a stud or expander member 102 and a clip or expansion member 104,both made of high strength steel to provide the resistance needed toovercome the forces acting as a result of the high installation torquerequired to set the anchor into the concrete. Existing designs consistof more than two assembled components.

The expander member 102 which is made of high strength steel to resistheavy duty tension and shear applications comprises a threaded section106, a proximal hex drive element 108 located at the top or beginning ofthe threaded section as a positive means of providing the spinning orrotational action to the anchor 100 during installation. The standardhex element 108 allows the use of a conventional type socket type drivefor fast access and easy removal.

At the opposite end of the expander member 102 is a specially designedstud configuration that provides a means to expand the undercutmechanism (or expansion member 104) which will provide the positive lockbetween the expander member 102 and the concrete of the supportstructure S. This stud configuration consists of longitudinal opposedfirst leading and second trailing flared portions 110 and 112,respectively. The trailing tapered portion 112, located towards thethreaded section 106, provides a means of expanding the undercutmechanism or expansion member 104 which in turn defines the undercutinto the concrete. At a proximal end of the trailing flared portion 112,is a collar 114 which is used to prevent the undercut mechanism orexpansion member 104 from moving onto the threaded section 106 of theexpander member 102.

The leading flared portion 110 provides a means of expanding the bottomportion, or distal end, of the expansion member 104, to thus completethe undercut/locking process. At the end of each flared portion is aspecially formed configuration to prevent the expansion member 104 fromrotating free of the expander member 102 during the initial undercutaction and during the final installation process.

The multiple function specially designed undercut mechanism/expansionmember 104 which is made of high strength steel comprises an expandablecollar 116, a leading support 118 and a pair of legs 120, reinforcedwith ribs 122, connecting the expandable collar 116 and the leadingsupport 118 together. The leading support 118 has a formed end 124 atthe bottom to reduce friction and serve as a means of providing a way offorcing the expandable collar 116 against the trailing flared portion112 of the expander member 102.

The expandable collar 116 is split at 126 to allow it to expand and hasat its trailing end a pair of inwardly directed tabs 128 which with thelegs 120 engage trailing and leading recesses 130 and 132, respectively,defined in the trailing and leading flared portions 112 and 110. Theexpansion member 104 is held captive by these longitudinal recesses 130and 132 thereby preventing the expansion member 104 from rotating withrespect to the expander member 102 and forcing it to work verticallywithout twisting. The expandable collar 116 defines opposed leading andtrailing edges 134 and 136, respectively. Between the flared portions110 and 112, the expander member 102 defines a cylindrical portion 138which allows the expandable collar 116 to be received in a collapsedposition when the anchor 100 is initially driven in the hole H.

Anchor Installation/Function

The anchor 100 is driven into the pre-drilled hole H until it is reachesits bottom (see FIG. 8A). A rotary drill with a hex drive socketattached is assembled to the external hex drive element 108. Tofacilitate the undercut action, the installer forces the expander member102 down by applying constant downward pressure thereon while it isspinning Once the expansion member 104 is frictionally engaged to thewalls of the hole H, the further downward displacement of the expandermember 102 causes the trailing flared section 112 to engage theexpansion member 104 and forces the latter to expand radially outward(see FIG. 8A), such that the rotation of the expander member 102resulting from it being connected to the rotary drill causes theexpansion member 104 to rotate (as it connected at its tabs 128 and legs120 to the trailing and leading recesses 130 and 132 of the expandermember 102). The spinning of the expansion member 104 causes itstrailing edge 136 to cut into the support structure S (e.g. ofconcrete), thus providing the initial undercut action.

Once the undercut action has been completed, the expander member 102 isset by assembling the nut N and washer W to a trailing end of itsthreaded section 106. The nut N is rotated until it is hand tightagainst the flat washer W and flush with the support structure S. As thenut N is tightened to a specified torque, it draws the expander member32 longitudinally and outwardly out of the hole H. Although the trailingflared portion 112 disengages from the collar 116, the trailing edge 136of the collar 116 remains set in the undercut (see FIG. 8B) in view ofits memory, for instance resulting from the trailing edge 136 havingbeen plastically deformed. As the expandable collar 116 remainsstationary by virtue of the positive locking engagement of its trailingedge 136 with the walls of the hole H, the leading flared portion 110causes the leading end of the collar 116 to expand outwardly (see FIG.8B). The expansion member 104 is prevented from rotating by its legs 120being laterally confined in the recesses 132 and being thus limited torelative longitudinal displacement therein. It is noted that theexpandable collar 116 may be spring loaded or biased outwardly, i.e. toa partly open or deployed position, to ensure the initial frictionalengagement thereof with the walls of the hole H.

The partial withdrawal of the expander member 102 from the hole H thuscauses the leading flared portion 110 to expand the collar 116 outwardlywith the leading edge 134 of the collar 116 engaging the walls of thehole H (see FIG. 8B) thereby completing the setting of the undercutmechanism/expansion member 104.

The anchor 100 thus provides the undercut needed to maintain the lockedposition of the installed anchor 100. The upper portion of the expansionmember 104 also contains a special configuration which includes a formedcutting edge 136 and/or surface to allow it to cut into the concrete andaggregate via the axial rotation provided by the drive tool spinning theexpander member 102. To increase resistance to wear, a special coating(e.g. abrasive, diamond coatings) or a series of hardened particles 140can be applied onto the surface and/or cutting edge 136 of the undercutportion of the expansion member 104.

The hex drive element 108 can take other forms as long as the expandermember 102 can be gripped from outside the hole H and rotated.

FIGS. 10A to 10D, 11A to 11C, 12A to 12C and 13A to 13C show fourvariants of the undercut wedge anchor 100 wherein the expansion member104 of FIGS. 9E to 9G has been modified, for instance at its formed end114 and tabs 128 (with similar adjustments to the trailing recesses130).

In the present non-slip wedge anchors (see FIGS. 1 to 7) and undercutwedge anchors (see FIGS. 8 to 13), the expansion of the expansion member(see, for instance, FIG. 7C of the non-slip wedge anchor and FIGS. 8Band 9E of the undercut wedge anchor) results from that at least proximalor trailing edge thereof, i.e. and upper section of the expandablesegments thereof, bites into or interferes with the peripheral concretewall of a receiving hole thereby preventing the assembly from sliding orcreeping upwards and cause the bolt to loosen in the hole defined in theconcrete structure. This prevents axial removal of the anchor from thehole. By so expanding the expansion member, resistance to axial pulloutis improved. The resiliency of the expansion member allows the anchor tobe easily inserted in the hole while urging the same against the wall ofthe hole to prevent the expansion member from rotating as a torque isapplied to a nut engaged to the bolt. The rotation of the nut causes thebolt to move translationally outwardly of the hole and thus causes aflared expander portion of the bolt to move axially into the stationaryexpansion member to expand the expansion member as per the way describedhereinbefore. With respect to the non-slip wedge anchor, this is wellillustrated in FIG. 6B, and in the case of the undercut wedge anchor,this is well shown in FIG. 8B.

In the case of the undercut wedge, there is a first expansion of theexpansion member followed by a rotation of the bolt such that theexpanded upper edge of the expansion member cuts into 360° of concreteand thus provides the undercut needed to maintain the locked position ofthe anchor. More specifically, the first expansion of the expansionmember is effected by applying a constant downward pressure on the boltso as to cause the expansion to move axially over an upper flaredportion of the bolt. Once the undercut action has been completed, theexpansion member is expanded by drawing a lower flared portion of thebolt into the expansion member via operation of a nut threadably engagedwith the threaded end of the bolt, thereby completing the setting of theundercut/expansion mechanism.

A main advantage of the above-described non-slip and undercut wedgeanchors resides in the fact that they provide a much stronger grip thanthat of known friction-based sleeve designs. In the case of the undercutwedge anchor, no separate drill bit is required to define the undercut.

C) Spiral Wedge Anchor (FIGS. 14 to 15)

FIG. 14A illustrates a spiral wedge anchor 200 having a stud or expandermember 202 defining a spiral and tapered lower end 204 for receiving aresilient coil or expansion member 206 (e.g. made of hard steel) which,in view of the initial frictional engagement of the coil 206 with thewall of the hole H in the support structure S, climbs along the tapersof the lower stud end 204 as the stud 202 is pulled rotatably outwardlyof the hole H, whereby the coil 206 is expanded outwardly radially forfurther contacting the hole H (as seen in FIG. 15), being firmly wedgedbetween the concrete S and the stud 202. An object O can thus be firmlyheld to the support structure S.

When referring throughout this disclosure and claims to terms such as“withdraw”, it is readily understood that the expander member is notcompletely removed from the hole, but rather partly displacedlongitudinally out of the hole and relative to the expansion member foreffecting the expansion of the expansion member. The anchored positionof the present anchors well illustrate this configuration (see FIGS. 1B,2B, 4B, 6B, 8B and 15).

1. An expansion wedge anchor for insertion in a hole delimited by awall, comprising an expander means and an expansion means, saidexpansion means being provided at a leading end of said expander means,said expander means comprising flaring means, said expansion means beingexpandable at a trailing end thereof and being adapted to engage thewall of the hole when said expander means is positioned in the hole,wherein upon longitudinal withdrawal of said expander means from thehole, said expander means displaces longitudinally relative to saidexpansion means with said flaring means thereof gradually causing saidtrailing end of said expansion means to expand, whereby a trailing edgeof said expansion means engages the wall of the hole.
 2. An expansionwedge anchor as defined in claim 1, wherein said trailing end isadapted, when expanded by said flaring means, to extend at an angle withrespect to a longitudinal axis of said expander means and to so engagethe wall of the hole, and wherein said expander means and said expansionmeans are each made of a single unitary component.
 3. An expansion wedgeanchor as defined in claim 1, wherein said expander means compriseproximally of said flaring means a threaded section adapted to beengaged, at a proximal end thereof outside of the hole, by a femalethreaded member which when rotated causes said expander means todisplace translationally along the hole.
 4. An expansion wedge anchor asdefined claim 1, wherein said flaring means comprise a flared end whichtapers towards said threaded section, an intermediate section beingprovided proximally of said flared end and having a diameter less thanthat of said threaded section, said intermediate section providing spaceto accommodate outwardly thereof at least part said expansion means in acollapsed position thereof at least for during insertion of said anchorin the hole.
 5. An expansion wedge anchor as defined in claim 1, whereinsaid expander means defines a shoulder at a junction of said threadedsection and said intermediate section for preventing said expansionmeans from reaching threaded section.
 6. An expansion wedge anchor asdefined in claim 1, wherein said expansion means comprises a leadingsupport located distally past said leading end, an expandable collarmeans provided proximally of said leading support and at least one legmeans extending outwardly of said expander means and connecting saidcollar means to said leading support, said collar means defining saidtrailing edge and being adapted to be outwardly expanded by said flaringmeans wherein said collar means is angled relative to a longitudinalaxis of the hole, said collar means flaring from a distal end thereoftoward a proximal end thereof, said proximal end defining said trailingedge, whereby said collar means engages the wall of the hole more deeplyproximally than distally.
 7. An expansion wedge anchor as defined inclaim 6, wherein said collar means defines a longitudinal split for eachsaid leg means.
 8. (canceled)
 9. (canceled)
 10. An expansion wedgeanchor as defined in claim 7, wherein at each said split, facing edgesof said collar means define cooperating mating means, and wherein saidcooperating mating means comprise tongue and groove elements providedtransversally on respective ones of said facing edges.
 11. (canceled)12. An expansion wedge anchor as defined in claim 6, wherein saidflaring means define a recessed longitudinal guide for each said legmeans for preventing said expansion means from rotating with respect tosaid expander means.
 13. (canceled)
 14. (canceled)
 15. An expansionwedge anchor as defined in claim 1, wherein said flaring means comprisea trailing flared portion which tapers away from said threaded sectionand which is adapted to expand said trailing end of said expansion meanssuch that said trailing edge thereof engages the wall of the hole,wherein said expansion means is adapted to rotate with said expandermeans, whereby upon rotation of said expander means said trailing edgeof said expansion means defines an undercut in the wall of the hole andsubsequently remains lodged in said undercut.
 16. An expansion wedgeanchor as defined in claim 15, wherein said flaring means furthercomprise an intermediate portion being provided distally of saidtrailing flared portion and having a diameter less than that of saidthreaded section, said intermediate portion providing space toaccommodate outwardly thereof at least part said expansion means in acollapsed position thereof at least for during insertion of said anchorin the hole.
 17. An expansion wedge anchor as defined in claim 15,wherein said expander means comprise proximally, for access outside ofthe hole when said expansion means is located in the hole, a drive meansengageable by a tool for rotating said expander means and said expansionmeans.
 18. An expansion wedge anchor as defined in claim 15, whereinsaid expander means further comprises a leading flared portion taperingtowards said threaded section, said intermediate portion extendingbetween said leading and trailing flared portions, wherein said leadingflared portion is adapted to expand a leading end of said expansionmeans.
 19. An expansion wedge anchor as defined in claim 18, wherein,once said undercut has been formed in the wall of the hole by a rotationof said trailing edge, said expander means is adapted to betranslationally withdrawn from the hole such that said leading flaredportion engages and expands said leading end of said expansion meanssuch as to engage the hole, a leading edge of said leading end of saidexpansion means extending into the wall.
 20. An expansion wedge anchoras defined in claim 19, wherein said leading end of said expansion meansextends at an angle with respect to the longitudinal axis of saidexpander means and so engages the wall of the hole.
 21. An expansionwedge anchor as defined in claim 18, wherein said expansion meanscomprise an expendable collar means defining said trailing and leadingends and said trailing and leading edges, a leading support provideddistally of said collar means, and at least one leg means extendingoutwardly of said expander means and connecting said collar means tosaid leading support, said collar means being adapted to be outwardlyexpanded by said trailing flared portion wherein said trailing end ofsaid collar means is angled relative to a longitudinal axis of the hole,said collar means being adapted to be outwardly expanded by said leadingflared portion wherein said leading end of said collar means is angledrelative to the longitudinal axis of the hole.
 22. (canceled) 23.(canceled)
 24. An expansion wedge anchor as defined in claim 21, whereinsaid leading and trailing flared portions of said expander means defineleading and trailing recessed longitudinal guides which respectivelyengage said leg means and tab means provided proximally at said trailingend of said expansion means, thereby preventing said expansion meansfrom rotating with respect to said expander means.
 25. (canceled)
 26. Amethod of setting an expansion wedge anchor in a hole delimited by awall, comprising the steps of: (a) providing an expander member and anexpansion member; and (b) displacing said expander member such as tocause a trailing end of said expansion member to engage the wall of thehole.
 27. A method as defined in claim 26, wherein in step (b) saidtrailing end is expanded such as to extend at an angle with respect to alongitudinal axis of said expander member, and wherein after step (b),step (c) consists of rotating said expander member and said expansionmember from outside of the hole such that the trailing end of saidexpansion member forms an undercut in the wall of the hole and remainslodged therein.
 28. (canceled)
 29. A method as defined in claim 27,wherein after step (c), step (d) consists of displacing said expandermember relative to said expansion member such as to cause a leading endof said expansion member to engage the wall of the hole.